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1.
在毛细管电泳仪上对萘心定、苯乙二醇和β - 苯基缩水甘油酸甲酯的外消旋体进行了拆分条件的研究。使用 pH 3.0、 10 mmol/L的磷酸-三乙醇胺电泳缓冲液, 10 kV反向电压,磺酰化β - 环糊精作为手性识别试剂, 3种化合物的对映体获得了满意的分离度。同时发现,一定含量的甲醇可以提高中性化合物对映体分离度。该法对苯氧基环氧丙烷和苯基环氧乙烷的对映体的分离同样有效。  相似文献   

2.
利用磺酰化β—环糊精的手性化合物毛细管电泳拆分   总被引:3,自引:0,他引:3  
在毛细管电泳仪上对萘心定,苯乙二醇和β-苯基缩水甘油酸甲酯的外消旋体进行了拆分条件的研究,使用pH3.0,10mol/L的磷酸-三乙醇胺电泳缓冲液,10kV反向电压,碘酰化β-环糊精作为手性识别试剂,3种化合物的对映体获得了满意的分离度,同时发现,一定含量的甲醇可以提高中性化合物对映体分离度,该法对苯氧基环氧丙烷和苯基环氧乙烷的对映体的分离同样有效。  相似文献   

3.
采用多糖类手性固定相,建立2-戊基-3-苯基-2,3-环氧丙醇对映体的高效液相色谱(HPLC)手性分析方法。考察了手性柱类型、流动相组成、流速及柱温对2-戊基-3-苯基-2,3-环氧丙醇对映体拆分的影响。结果表明,以Chiralcel OD-H色谱柱(25×0.46cm,5μm)分离,采用正己烷-异丙醇(V/V,90∶10)作流动相,在流速为0.8 mL·min-1,柱温25℃,检测波长210nm的条件下,2-戊基-3-苯基-2,3-环氧丙醇对映体能达到基线分离,且具有较好的重复性和稳定性,可用于对映体的拆分及质量控制。该方法也适用于2-戊基-3-苯基-2,3-环氧丙醇类似物质的手性拆分。  相似文献   

4.
王敏 《色谱》2014,32(2):198-203
对比了商品化的淀粉型手性固定相Chiralcel OJ-H和纤维素型手性固定相Chiralpak AD-H柱在正相条件下对扁桃酸系列8个化合物的拆分,结果表明Chiralcel OJ-H柱对扁桃酸系列化合物具有更强的手性识别能力,8个外消旋扁桃酸化合物在36 min内都得到了基线分离。研究发现,扁桃酸苯环上的取代基对其拆分的难易程度影响很大,其电子诱导效应影响扁桃酸类化合物在固定相上的保留时间,其空间位阻效应是扁桃酸在固定相上被拆分成败的决定因素。通过对比分析扁桃酸和手性柱的结构,探讨了可能的手性拆分机理是基于Chiralpak AD-H(Chiralcel OJ-H)手性固定相和扁桃酸系列化合物之间的氢键-氢键、偶极-偶极、π-π电子相互作用以及空间适应性等诸多因素的综合影响,其中空间适应性起到至关重要的作用。本研究可为一些实际光学活性扁桃酸及其类似物的对映体纯度测定与拆分研究提供参考。  相似文献   

5.
在使用10mmol/L NH4Ac(pH 4.5),30mmol/L Cu(Ac)2和60mmol/LL-羟基脯氨酸的优化条件下,13min内拆分了3种α-羟基酸对映体(DL-苹果酸、DL-苦杏仁酸和DL-对溴苦杏仁酸),除苹果酸外均获得了满意的拆分结果;考察了电泳缓冲液组成、pH值等影响分离效果的因素。  相似文献   

6.
利用正相高效液相色谱法在多糖衍生物手性固定相(OJ-H、OD-H、AD-H或AS-H)上成功地分离了一系列(31个)氰醇对映体的乙酰化或丙酰化衍生物,并拆分了3个脂肪族氰醇对映体的乙酰化衍生物。探讨了这些外消旋体在这四支手性柱上的色谱行为,通过考察流动相组成、流速、进样浓度和温度等因素对对映体拆分效果的影响,优化了色谱分离条件。方法已应用于脂肪酶催化转酯化拆分反应中手性氰醇衍生物的光学纯度的鉴定。  相似文献   

7.
合成了外消旋5-乙氧基羰基特特拉姆酸甲酯(1)和顺/反式5-乙氧基羰基- 4-羟基-2-吡咯烷酮(2),并利用手性高效液相色谱制备少量的单一对映体标样进行圆二色光谱表征.在此基础上,系统研究了这3对外消旋体化合物在Chiralpak AD-H和Chiralcel OD-H手性柱上的液相色谱拆分行为和对映体出峰顺序.采用正己烷-异丙醇(体积比60 : 40)作流动相,外消旋化合物1在Chiralpak AD-H柱上得到很好的拆分,k1、α和RS分别为0.99、2.65和12.5;采用正己烷-异丙醇(体积比80 : 20)作流动相,化合物2的4个立体异构体可以同时在Chiralpak AD-H柱上得到基线分离,反式-2对映体的 k1、α1和RS1分别为1.69、1.12和1.56,顺式-2对映体的k3、α2和RS2分别为2.58、1.16和2.28.  相似文献   

8.
以万古霉素和1,6-己二异腈酸酯为单体,通过界面聚合法在聚砜基膜上制备了万古霉素手性高分子膜.利用红外光谱及扫描电子显微镜对该膜进行了表征.将其用于青霉素及头孢菌素类药物的重要中间体苯甘氨酸的手性拆分,通过优化单体摩尔比、界面聚合时间及外消旋体溶液浓度等分离参数,可达到超过70%的D-苯甘氨酸对映体过剩值的手性分离.通过比较研究手性膜吸附、固相萃取、膜色谱、膜渗析和膜超滤过程,发现手性膜上优先吸附的对映体L-苯甘氨酸并不是各种模式下优先透过的对映体,结合外消旋体的缔合特性,提出了"吸附-缔合-扩散"的手性膜分离机理.  相似文献   

9.
张文华  洪灯  雷美康  胡晓莉  侯建波  谢文  徐敦明  伊雄海  李优 《色谱》2021,39(12):1347-1354
建立了基于超高效合相色谱技术(UPC2)的克伦特罗对映体拆分方法,并对所建立的方法进行了方法学考察及应用。实验考察了两种克伦特罗对映体标准溶液的稳定性,并对手性色谱柱、助溶剂、系统背压、色谱柱温度等色谱分离条件进行了优化。采用Acquity Trefoil AMY1 (150 mm×3.0 mm, 2.5 μm)手性色谱柱进行分离,以超临界CO2-含0.5%(v/v) 10 mol/L醋酸铵的甲醇溶液为流动相,以流速2.0 mL/min梯度洗脱,检测波长为241 nm,进样体积为10 μL,系统背压为13.8 MPa,柱温为40 ℃时,两种克伦特罗对映体分离效果最好。两种克伦特罗对映体的线性范围为1.0~20.0 mg/L,相关系数均大于0.9997,仪器检出限(S/N=3)均为0.5 mg/L。10.0 mg/L混合标准工作溶液重复进样6次,(+)、(-)克伦特罗对映体峰面积的相对标准偏差(RSD, n=6)分别为0.65%和0.76%。应用该方法对市售克伦特罗外消旋体标准品进行拆分,采用外标定量法计算克伦特罗外消旋体标准中间溶液10.0 mg/L中两种克伦特罗对映体含量,其中(+)-克伦特罗的含量为5.6 mg/L, (-)-克伦特罗的含量为5.5 mg/L。该计算结果与文献报道的工业品克伦特罗外消旋体中(+)-克伦特罗与(-)-克伦特罗的比例为1.02∶1.00基本相符。该方法具有分析速度快、分离效果好、有机溶剂消耗少等特点,适用于克伦特罗对映体的拆分,为其他手性化合物的拆分、药效精细分析和产品质量评定提供了可靠的技术支持。  相似文献   

10.
周志强  王鹏  江树人  王敏 《色谱》2003,21(1):44-45
 合成了直链淀粉-三(3,5-二甲基苯基氨基甲酸酯),涂于氨基丙烷化硅胶上制得高效液相色谱手性固定相,并利用该固定相对外消旋丙烯菊醇对映体进行了拆分。考察了流动相中异丙醇含量对分离效果的影响。  相似文献   

11.
Racemic mandelic acid was resolved through R(-)-mandelic acid salt with L-phenylalanine methyl ester in ethanol; the antipode S(+)-mandelic acid was then recovered from the mother liquid. Both were prepared in high yield and in highly optical purity. Carboxypeptidase A was also used in the separation of S(+)-mandelic acid via selective hydrolysis of hippuryl-RS-mandelic acid. Comparison of the two methods was discussed.  相似文献   

12.
Two enantioselective fluorescent sensors, namely, the 1,1'-binaphthol (BINOL)-amino alcohol (S)-1 and the H(8)BINOL-amino alcohol (R)-2, have been prepared as a pseudoenantiomeric pair. These two compounds have the opposite chiral configuration at both the axially chiral biaryl centers and the amino alcohol units. In methylene chloride solution, (R)-mandelic acid greatly enhances the emission of (S)-1 at λ(1) = 374 nm and (S)-mandelic acid greatly enhances the emission of (R)-2 at λ(2) = 330 nm. A 1:1 mixture of (S)-1 and (R)-2 was used to interact with mandelic acid at a variety of concentrations with various enantiomeric compositions. It was found that both the concentration of mandelic acid and its enantiomeric composition can be directly determined by measuring the sum and difference of the fluorescence intensities at λ(1) and λ(2).  相似文献   

13.
A practical enantioselective fluorescent sensor for mandelic acid   总被引:1,自引:0,他引:1  
A novel optically active bisbinaphthyl fluorescent sensor, (S,S)- or (R,R)-1, is designed for the recognition of chiral alpha-hydroxycarboxylic acids. A convenient method has been developed to synthesize this compound. It is observed that (S)-mandelic acid enhances the fluorescence intensity of the (S,S)-sensor significantly more than (R)-mandelic acid does. The enantioselective fluorescent response is confirmed with the observation of a mirror image relationship for the interaction of (S,S)- and (R,R)-sensors with mandelic acid. The enantioselectivity in fluorescence response [(I(S) - I(0))/(I(R) - I(0)) = 2.49] is quite high, which makes the sensor useful for practical application. The fluorescence intensity change of the sensor is found to be linearly related to the enantiomeric composition of mandelic acid. This sensor is potentially useful for the combinatorial search of chiral catalysts for the asymmetric synthesis of alpha-hydroxycarboxylic acids.  相似文献   

14.
Crosslinked α- and β-cyclodextrin gels (α-CD-E and β-CD-E) were used for the chromatographic resolution of racemic mandelic acid and its derivatives. β-CD-E bound L -(+)-isomers preferentially over D -(?)-isomers and resolved DL -methyl mandelate to give a D -(?)-isomer of 100% optical purity in the first fraction. Mandelic acid, ethyl mandelate, and O-methylated mandelic acid yielded resolutions of 65–83% in initial fractions. α-CD-E, on the contrary, bound D -(?)-isomers more strongly than L -(+)-isomers, resolving DL -methyl mandelate to a smaller extent than β-CD-E. Binding of DL -mandelic acid and DL -methyl mandelate on β-CD-E was studied quantitatively by the equilibrium method. β-CD-E has a similar binding capacity to starch with 1:1 stoichiometry but bound much more strongly than starch. β-CD-E has the same mode of selectivity as starch for the asymmetric binding of the mandelic acid derivatives, but α-CD-E has a reverse selectivity to β-CD-E and starch.  相似文献   

15.
The colorimetric enantiodiscrimination between mandelic acid and L-proline-Cu(II) is exploited to develop enantioselective indicator displacement assays. The sensitivity of the assay could be tuned by using a colorimetric indicator. The chromophoric ligand, pyrocatechol violet, effectively competes with the mandelic acid guest for open coordination sites on L-proline-Cu(II). The DA could be increased to 0.12 by changing the ratio of(+)- and(à)-mandelic acid concentrations that were found to be optimal from the displacement experiments. The resultant enantiomer excess versus DA relationship is linear. From the calibration curves, the absorbance values of the unknowns may be calculated for the enantiomeric excess value and the colorimetric enantiodiscrimination of mandelic acid can thus be obtained.  相似文献   

16.
Sulaiman Y  Kataky R 《The Analyst》2012,137(10):2386-2393
Chiral conducting polymers prepared by electropolymerising PEDOT in the presence of chiral anions such as hyaluronic acid and anionic collagen or in a chiral nematic phase (hydroxypropyl cellulose, HPC) show excellent chiral acid recognition. This paper demonstrates the enantioselective recognition and transfer of protonated mandelic acid and protons using chiral PEDOTs. Discrimination between (R)-(-)- and (S)-(+)-mandelic acid was observed using cyclic voltammetry and square-wave voltammetry.  相似文献   

17.
A chiral nitrogen-containing calix[4]crown 2 bearing optically pure 1,2-diphenyl-1,2-oxyamino residue at lower rim showed excellent chiral recognition between enantiomers of mandelic acid. Using competitive 1H NMR titration the ratio of association constants of (S)- and (R)-mandelic acid with the chiral calix[4]crown was determined to be 102, that is 98% de, which is the best result obtained from artificial receptors for the chiral recognition of mandelic acid up to now.  相似文献   

18.
Leitch RE  Rothbart HL  Rieman W 《Talanta》1968,15(2):213-219
The racemic alcohols, 2-methylbutanol-l, 3-methylbutanol-2, pentanol-2 and hexanol-2 have been esterified with optically active mandelic or lactic acid, and the resultant mixtures of diastereoisomeric esters separated chromatographically with an optically inactive sulphonated polystyrene resin as the stationary phase and water or dilute aqueous sodium sulphate as the mobile phase. Lactate esters were more easily separated than mandelate esters. The Chromatographic separation of 26 mmole of (+/-)-3-methyl-2-butyl(+)-lactate and subsequent hydrolysis of the fractions containing only the ester of the (+)-alcohol yielded 1-2 mmole of pure 3-methyl-2-butanol.  相似文献   

19.
The resolution of racemic 1-(3-methoxyphenyl)ethylamine with (S)-mandelic acid by diastereomeric salt formation can be made more economical by application of the Pope-Peachey method. This resolution was further improved upon by the addition of small amounts of a nucleation inhibitor, which prevents the formation of crystals of the more soluble diastereomer. The mandelic acid left in the solution is then used for further crystal growth of the less soluble diastereomer, furnishing high yields and diastereomeric excesses. Slow cooling and grinding of the crystals formed lead to increased secondary nucleation and thus to more consumption of the less soluble diastereomer and even better results.  相似文献   

20.
Novel chiral receptors based on l-phenylalanine and l-valine have been synthesized and their chiral recognition properties toward mandelic acid and N-tosyl α-amino acids are studied. The phenylalanine-based receptor undergoes enantioselective gel formation with R-mandelic acid and N-tosyl-d-valine, whereas the valine-linked receptor in their presence results in the formation of precipitates.  相似文献   

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